Can we stick to potions? I can't see why it is implausible for you that a test fails to identify a magic potion with an effect that only triggers in a specific circumstance. You are not poisoned what effect are you supposed to feel when drinking a cure poison potion?
It feels like there are relevant definitions of "test" that fit with the books use of it (where in one place it sounds like it just happens and where it nowhere discusses potential failure) where the chance of failure could either be not implied or small enough as to be negligible (or at least as not implied or as small as other things we don't roll for).
In the OED, the relevant verb entry for test (the other three seem to be about attesting to things legally, a variant for taste, and a variant for tess=bloke).
- Definition 1 includes: "to assay" (my note: Of course some types of assays can and do certainly fail, others are extremely reliable)
- Definition 2a includes: "to ascertain the existence, genuineness, or quality of"
They have not the means of testing the statements. - Blackwood's Edinburgh Magazine, Septembr 591/1
- Definition 4 is: "Chemistry. To subject to a chemical test."
(The first quote for this one is from a definition of assay).
The urine..must be tested with litmus paper - G.E. Day translation of J.F. Simon, Animal Chemistry vol II. 135. (my note: lithmus paper is apparently very reliable at distinguishing pH < 4.5 vs. pH > 8.3).
I have tested the water in all the wells. - M.E. Braddon, Fatal Three vol. 1 v. 98.
So, going to assay's entry as a verb:
- Definition 1.4.d (the first that isn't obsolete or particularly about metal): "To test the strength of a substnce by means of a a test on an organism."
Drugs..can be assayed with a sufficient degree of accuracy by biological methods. - Lancet 20 October 820/1
- Definition 1.5 (obsolete except historical): "To try by tasting. spec. To taste foot or drink before it is offered to a prince or lord."
Under taste, I note the following definitions that might be even more relevant:
- II.6.a - "To try the flavour or quality of by the sense of taste; [...] spec. to test the quality of by tasting for trade purposes."
- II.6.b - "To test or certify the wholesomeness of (food provided) by tasting it"
- II.6.d - "figurative. To make trial of as by the sense of taste; to try the quality of."
Looking around for other quotes, I offer the following:
- "The mouth tastes words as the palate tests food." - Job 34:3
- "Alex's blindfolded spice taste test" - Food network video [of course some of these are generally set-up to be complicated and others easy; B/X doesn't seem to imply it is trying to be hard]
- "Some people taste cocaine to test its purity" - Addiction Resource
- "How accurate are glucose test strips, ... Contour Next from Bayer: 100%" - healthline.com (presumably rounding to 100% in the estimate; but lets face it there is a non-zero chance a player will die in the act of rolling a die too)
- "Can we tell the difference? Coke, Pepsi, Sprite, 7up, Mountain Dew, Kickapoo My wife and I did a blindfolded test to see if we can tell the difference between these popular sodas" - Keep it Riyal on Youtube (they were 100% on the similar flavors from each other, and I imagine it would be astounding for someone to confuse Coke with 7up or 7up with Mt.Dew)
- "In mineralogy also, the traditional skills of appraising minerals by appearance, texture, smell, and taste gave way to methods of chemical analysis." - Holmes and Levere, eds. (2002)
- "Compare this with the author's description of leaved niter: 'it is not very salty, but has as it were the taste of vinegar when you touch it with your tongue, and it gives a flame on the fire.' It is clear that the Ars Alchemie is here describing a test for differentiating two chemicals..." - Holmes and Levere (eds. 2002).
Over in the Roget's Thesaurus (4th, complete and unabridged):
- 489. Experiment
489.8 Verbs
includes: run a sample, test, try, verify, give a try, sample, taste, assay
In terms of gaming at the time, the 1e DMG statements do seem a bit contradictory "However, even a small taste should suffice to identify a potion in some way - even if it is just a slight urge. As Dungeon Master you should add a few different sorts of potions, both helpful and harmful, of such natures as to cause difficulties in identification." But if there was any intent to institutionalize this, it feels like they would make potions come in groups to enable this confusion, have more than 3 bad kind of potion (delusion, poison, philter of love), and more certainly, have provided a table to help in this misleading! I mean, what isn't there a table for that he wants to happen regularly!?!? They gives such a table for cursed scrolls. And why on earth would they make poisons usually be odorless and colorless if they want to trick people into drinking them!?! (Delusion on the other hand makes it sound like you're supposed to pick a different potion for it to taste like, there is a 90% chance they will all agree). As much as I like the DMG, this seems one of those places where the "different potions" remark is poorly conceived given all of the other rules (and unhelpful in interpreting B/X).
Finally, if the hang-up is on the fact that it doesn't say there is no chance of failure (that there is at least some small chance), I also note that the book gives no rules on tripping during the regular movement phase.- and yet apparently "slips, trips, and falls cause nearly 700 workplace fatalities per year" according to OSHA (no separation there) and "stair-related injuries send an estimated 1.08 million people to emergency departments every year" according to Blazewick, et.al (2018). It also gives no chance of failure in eating meals - yet around 5,500 people die from choking in the US each year (NSC.org) with over 10,000 ER visits for it (Saccomanno, et.al. 2003). Although, to be fair, the choking ones are mostly children and the elderly and not adventurers.